Introduction. Since the introduction of 3rd generation Metal-on-Metal-Hip-Resurfacing-Arthroplasty (MoMHRA), thousands of such prostheses have been implanted worldwide in younger patients with end-stage hip osteoarthritis. However, no independent centre has reported their medium-to-long term outcome. The aim of this study is to report the ten year survival and outcome of the Birmingham Hip Resurfacing (BHR), the most commonly used MoMHRA worldwide. Methods. Since 1999, 648 BHRs were implanted in 555 patients, the majority of which were male (326). The mean age at surgery was 52.1years (range: 17–82), with primary OA as most common indication (85%). Mean follow up was 7.1years (range: 1–11). The Oxford Hip Score (OHS) and UCLA questionnaires were sent to all patients. Implant survival was established, with revision as the end point. Sub-analysis was performed by gender, femoral component size (small: <45mm, standard: 46–52, large: >53mm) and age at surgery (young:<50yrs, old:>50yrs). Results. Preliminary results show that survival and clinical outcome were better in men than women (p=0.013) and in patients with large and standard components compared to small (p=0.005). In women the survival and clinical outcome were worse in the young than the old (p=0.049). In men there was no difference in survival or clinical outcome between the young and old (p=0.106). In young men the 10-year survival was 95%, the mean OHS was 45 and the mean UCLA score was 8.1. Conclusion. The results of resurfacing are good in men. They perform particularly well in the young and highly active men who tend to have problems with conventional hip replacements

INTRODUCTION. Whilst there is a great deal of research on hip implants, few studies have looked at implant orientation and the subsequent effect upon the wear performance of a hip resurfacing. This study aimed to measure implantation angles through radiographic analysis and linear wear for retrieved acetabular cups in order to investigate possible causal links between wear and implant orientation. MATERIALS & METHODS. Seventy Birmingham Hip Resurfacing (Smith & Nephew, UK) cups with known time in vivo were analysed. Linear wear of retrieved cups were assessed using a Talyrond 290 roundness machine. Deviations from the characteristic manufactured profile, was identified as a region of wear. Polar measurements across the wear region were taken to determine wear. The linear wear rate (LWR) of a component was defined as the linear wear (μm) divided by the duration of the implant life in vivo (years). Cups which showed the wear crossing over the edge of the cup were classified as edge loaded (EL). For all non-edge loaded (NEL) cups, the wear area was within the bearing surface. Cup orientation angles were conducted for 31 cups. This was determined by superimposing BHR models of appropriate size, generated by CAD ProEngineer Wildfire 4, onto anterior-posterior x-rays. Anatomical landmarks and specific features of the BHR were used as points of reference to determine cup version and inclination angles. RESULTS. Forty two cups were classed as EL, showing regions of wear extending beyond the edge of the cup. Twenty eight were classed as NEL. The EL group had an average LWR of 25.4(±8.05 95% CL) μm/yr, whilst the NEL group generated an average LWR of 1.45 (±0.34 95% CL) μm/yr, a statistically significant difference (p<0.05).a Following radiographic analysis, 23 cups were classed as EL, showing regions of wear extending beyond the edge of the cup. Eight were classed as NEL. Cups in the EL group showed average inclination and version angles of 54.35° (±5.37° 95% CL) and 22.43° (±5.23° 95% CL). Average inclination and version angles of cups in the NEL group were 45° (±7.20° 95% CL), and 14.88° (±3.38° 95% CL) respectively. Inclination and version angles between the two groups were statistically significant (p<0.05). DISCUSSION. Through linear wear and radiographic analysis, the current study has shown that mal-positioned resurfacing devices classed as EL had higher linear wear than the NEL cups. Edge loaded cups examined in this study showed significantly higher inclination and anteversion (p<0.05) than the non-edge loaded devices. This indicates that component wear is closely associated with in vivo orientation. The success of any implant is dependent upon implant orientation both in version and inclination angles. The correct implant orientation will help to ensure that wear occurs within the bearing surfaces, maintaining an optimal lubrication regime and low wear

There is a lack of evidence surrounding selective patella resurfacing, but patella cartilage loss at time of total knee arthroplasty (TKA) is often used as an indication in those who perform it. This study compares the outcomes of TKA without patella resurfacing in patients with and without patella cartilage loss (PFOA).

Prospective case control study of 209 consecutive patients undergoing cruciate retaining single radius TKA without patella resurfacing for KL≥3 osteoarthritis. The presence and location of full thickness patella cartilage loss was documented intra-operatively at TKA, identifying n=108 cases with PFOA (mean age 70±9.7, mean BMI 31±6.2, 72 (67%) female) Vs n=101 controls without PFOA (age 68±9.2, BMI31±5.6, 52 (51%) female). Primary outcome measure was improvement in the Oxford Knee Score (OKS) at one year.

There were more females in the PFOA group (67% Vs 51%, p=0.037), but no other preoperative differences. There was no difference in preoperative OKS between patients with patella cartilage loss (20.6±7.9) and those without (21.0±7.2, p=0.720). There was no difference in OKS improvement following TKA without patella resurfacing between those with full thickness patella cartilage loss (14.2±9.8) and those without (15.4±9.5, p=0.365). Facet involvement (number and location) did not affect OKSs. No differences were found in the individual OKS questions between groups (p>0.05).

There was no difference in one-year OKS or improvements therein between patients with and without full thickness patella cartilage loss treated with single radius cruciate retaining TKA without patella resurfacing, questioning its use an indication for selective patella resurfacing.

The use of Birmingham hip resurfacing (BHR) remains controversial due to the increased revision rate in female patients. We compared the outcomes of BHR in female patients to an age matched total hip arthroplasty(THA) cohort. We reviewed the pain, function and total Harris Hip Scores(HHS), and Kaplan-Meir survivorship for BHR and THA cohorts from a prospective regional arthroplasty database.

There were 234 patients in each cohort, with mean age of 51 years. The BHR cohort had significantly better function and total HHS at all points of the 5-year study, but not for the post-operative pain score. The 5-year revision rate for the BHR cohort was significantly higher than the THA cohort (6.8% vs 3.4%, p=0.001). The main reason for revision in the BHR cohort was aseptic loosening (n=8), followed by metallosis (n=3). The 5-year Kaplan-Meier survivorship was 92.6% (95% CI±1.7%) and 96.4% (95% CI±1.3%) for the BHR and THA cohort (p=0.001).

BHR can give significantly better functional outcomes than THA. The vast majority of female patients were happy with BHR and did not need further surgery at the 5-year stage. This is somewhat at odds with the recent reputation of the procedure. The 10-year result of the same cohort is warranted to provide further data. Our study is not a recommendation to still offer BHR to female patients, but rather to inject a note of realism into the debate. There are implications for future implant development in that these results do validate resurfacing as a functionally valuable option for active patients.

Introduction

Metal on metal hip resurfacing (MMHR) has been advocated for the younger patient for several reasons including for the preservation of bone stock and ease of revision to total hip replacement (THR), thus ‘buying an additional operation’ for the patient. This rationale however assumes a good functional outcome after the revision to a THR and that the results of the ‘revision primary’ will not be compromised by the resurfacing which preceded it. We present our data on a consecutive series of 68 revised MMHRs.

The Global Conservative Anatomic Prosthesis (Global CAP) is an uncemented press fit humeral resurfacing implant developed by DePuy. We report a single surgeon series of Global CAP prostheses implanted in Norwich.

103 procedures were carried out between 2006 and 2011, in 93 patients. Mean age was 72 years (range 43 to 90). Patients were followed up for a mean 8 months (range 0 to 56). Pre-operative Oxford shoulder scores were recorded in a preadmission clinic and an Oxford score questionnaire was sent to patients post-operatively in December 2011. The mean score preoperatively was 19, rising to 28 postoperatively.

Two patients developed rotator cuff tears and have been revised to reverse polarity arthroplasty. One is pending revision for a cuff tear.

This prosthesis shows promise at this early stage for compensated glenohumeral arthritis when a bone preserving procedure is desirable.

INTRODUCTION

Studies have suggested that there is a reduction in head-neck-ratio (HNR) associated with MoMHRA. A reduction in HNR at operation would decrease range of movement and increase impingement risk. Impingement could lead to 20 edge loading, increasing wear. Serum ion levels of Chromium (Cr) and Cobalt (Co) are surrogate markers of wear. Although acetabular component orientation has been shown to contribute to wear and PT development, the role of a decrease in HNR has only been highlighted in PT development. This study aimed to measure changes in HNR that occur at resurfacing and determine any gender- and component size-specific differences. In addition it aimed to determine whether changes in HNR could be associated with increased wear.

Background

Hip resurfacing arthroplasty (HRA) has seen a recent revival with third generation Metal-on-Metal prostheses and is now widely in use. However, safety and effectiveness of hip resurfacing are still questioned. We systematically reviewed peer-reviewed literature on hip resurfacing arthroplasty to address these issues.

Introduction

Metal-on-metal hip resurfacing (MOMHR) is a good surgical indication for young active patients. However, it cannot be used in patients with an excessively short femoral head/neck. To address these cases, a new surgical technique has been developed comprising femoral head augmentation using impacted morcellized bone grafts.

INTRODUCTION

Although simulation studies have shown superior wear properties of metal-on-metal articulations, increased concern exists regarding the excess in-vivo wear of a small number of Metal-on-Metal-Hip-Resurfacing (MoMHRA) implants. Serum ion levels of Chromium (Cr) and Cobalt (Co) are surrogate markers of wear. Risk factors associated with increased wear include female gender, small components, dysplasia, cup orientation outside safe zone and femoral head downsize during surgery with an associated decrease in Head-Neck-Ratio (HNR). However, these factors are interlinked. This study aims to identify the factors that are most important for subsequent wear of MoMHRA, by performing a multivariate analysis.

Introduction

It was the purpose to evaluate the biomechanical changes that occur after optimal and non-optimal component placement of a hip resurfacing (SRA) by using a subject specific musculoskeletal model based on CT-scan data.

Introduction

Although femoral neck fractures remain a concern in short term failures for hip resurfacing, acetabular component position and fixation are increasingly being recognized as causes of mid term failures for hip resurfacing. This study aimed to evaluate the migration pattern of a cobalt chrome, beaded acetabular component for a metal on metal hip resurfacing.

Objectives

Osteochondral ankle defects (OCDs) mainly occur in a young, active population. In 63% of cases the defect is located on the medial talar dome. Arthroscopic debridement and microfracture is considered the primary treatment for defects up to 15 mm. To treat patients with a secondary OCD of the medial talar dome, a 15-mm diameter metal implant (HemiCAP ®) was developed. The set of 15 offset sizes was designed to correspond with the anatomy of various talar dome curvatures. Recently, two independent biomechanical cadaver studies were published, providing rationale for clinical use. The present study was undertaken to evaluate the clinical effectiveness and safety of the metal implantation technique for osteochondral lesions of the medial talar dome in a prospective study.

Hip resurfacing has grown rapidly since its introduction in the United States, as an alternative to total hip replacement in the younger, active patient. Some studies have suggested a steep learning curve and a higher complication rate when compared to THR. Existing studies have originated from the pioneering surgeons, using a specific type of resurfacing implant. The purpose of this study was to look at the experience of a single, non-inventor surgeon with the adoption of hip resurfacing, using 3 different implants.

Hip resurfacing arthroplasty is an established and effective intervention for osteoarthritis of the hip in the young active patient, relying on the principle of femoral bone-stock preservation. A recognised mode of failure is neck thinning leading to radiological evidence of neck collapse and clinical failure.

We report on a series of these slow-neck-failure patients and highlight the increased incidence of this phenomenon in post-menopausal female patients. This is a single operator, single implant series; 172 cases were identified from databases at our institution. 76 were female, mean (SD) age 52 (7) years. 96 were male, mean (SD) age 51(12) years. 15 (8.7%) patients required revision. 12 (80%) were female, 9 (75%) of these were due to slow neck failure. In the men one patient developed ALVAL requiring removal of his bilateral hip resurfacings, the other failure mode was early femoral neck failure. Mean time to failure was 6 months in men and 37 months in women. This difference in failure rates is also seen in the NJR figures.

This review confirms the relatively high incidence of premature failure in post-menopausal females. NICE guidance in 2003, currently under review, stated that resurfacing is indicated in male patients up to 65 and female patients up to 60. As a result of this study we are currently advising post-menopausal patients that this risk of early failure may make total hip replacement a preferable option to resurfacing arthroplasty.

INTRODUCTION

The advantages of large diameter metal on metal total hip arthroplasty (MoM THA) and hip resurfacing arthroplasty are decreased wear rate, preservation of bone stock, anatomical restoration and enhanced stability. Large amounts of metal wear particles and metal ions are released which may induce adverse reactions including local soft tissue toxicity, hypersensitivity reactions, bone loss and risk of carcinogenesis. Aseptic loosening can be the result of a peri-prosthetic osteolysis generated as a result of a biological response to particulate wear debris.

No reports in the literature exist as to whether circulating levels of Chromium (Cr) and Cobalt (Co) decrease upon removal of a symptomatic large diameter MoM implant or whether levels remain high due to the effect of metal ions debris left behind in the soft tissues after revision surgery.

Introduction

Metal on metal articulations produce chromium (Cr) and cobalt (Co) debris, particularly when the articulations are worn in. High levels in the peripheral blood are indicative of excess wear and may cause adverse effects. The present RCT investigates metal ion levels and the relationship of Co, Cr ions and lymphocyte counts during the running-in period.

Background

Metal on metal hip resurfacing has become popular worldwide for younger patients because of perceived advantages in function and ease of revision, due to bone conservation. Joint Registry data have shown increased risk of early failure, particularly in younger females. There have been few studies comparing the outcome of resurfacing to cemented total hip arthroplasty (THA).

Introduction

Controversy exists as to whether the short external rotator tendons and capsule of the hip should be repaired after posterior approach primary total hip arthroplasty (THA). Recent studies using radiopaque markers have demonstrated that reimplantation of these muscle tendons fail early and may not prevent post operative dislocation.

Aims

Femoral periprosthetic fractures are rising in incidence. Their management is complex and carries a high associated mortality. Unlike native hip fractures, there are no guidelines advising on time to theatre in this group. We aim to determine whether delaying surgical intervention influences morbidity or mortality in femoral periprosthetic fractures.